[srslte-users] VoLTE with srsenb and Amarisoft Callbox IMS

[Andre Puschmann]

Hey Norbert,

from your description it's not obvious what the issue might be. Actually
there could be many things.

I think for this sort of issues it's best to create a ticket on Github
and post all relevant logs, PCAPs, etc.


Thanks
Andre


On 9/6/21 11:56, Englberger, Norbert wrote:
>  
> 
> Hi,
> 
>  
> 
> we are trying to expand our existing 4G setup by connecting multiple
> srsenb to our Amarisoft Callbox for Data and Voice services.
> 
>  
> 
> Right now, we could connect the eNodeB with the Callbox and Data
> services (surfing the Internet) work, Voice calls fail.
> 
> When we start a Call the UE loses the complete connection to the Network
> and has to be reconnected manually ( switching to Airplane mode one and
> off).
> 
>  
> 
> After our first analysis of the PCAP files generated by the eNodeB
> showed a Malformed “E-RABSetupResponse”, which could be fixed by
> reconfiguring the “ims” APN to use IPv4 only.
> 
>  
> 
> Since VoLTE still fails, we took a further look into the PCAPs and
> discovered the following:
> 
>  
> 
> No.        Time      Source  Destination        Protocol             
> Length  Info
> 
> 1             0.000000                                            
> S1AP/NAS-EPS 131         InitialUEMessage, Attach request, PDN
> connectivity request
> 
> 2             0.000852                                            
> S1AP/NAS-EPS 33           DownlinkNASTransport, ESM information request
> 
> 3             0.020218                                            
> S1AP/NAS-EPS 103         UplinkNASTransport, ESM information response
> 
> 4             0.020907                                            
> S1AP/NAS-EPS 226         InitialContextSetupRequest, Attach accept,
> Activate default EPS bearer context request
> 
> 5             0.060364                                            
> S1AP     38           InitialContextSetupResponse
> 
> 6             0.100302                                            
> S1AP/NAS-EPS 59           UplinkNASTransport, Attach complete, Activate
> default EPS bearer context accept
> 
> 7             7.540231                                            
> S1AP/NAS-EPS 105         UplinkNASTransport, PDN connectivity request
> 
> 8             7.540914                                            
> S1AP/NAS-EPS 131         E-RABSetupRequest, Activate default EPS bearer
> context request
> 
> 9             7.540994                                            
> S1AP     31           E-RABSetupResponse
> [RadioNetwork-cause=not-supported-QCI-value]
> 
> 10           15.540146                                          
> S1AP/NAS-EPS 105         UplinkNASTransport, PDN connectivity request
> 
> 11           15.540839                                          
> S1AP/NAS-EPS 34           DownlinkNASTransport, PDN connectivity reject
> (Multiple PDN connections for a given APN not allowed)
> 
>  
> 
>  
> 
> In lines 1-6 the UE connects to the Network and to the APN “internet”.
> This seem to work fine.
> 
> Then the UE tries to connect to the APN “ims” and after a while retries
> to connect, where the second connection is rejected. (Shouldn’t there be
> any “reject” or “accept” message between the two connection requests?)
> 
>  
> 
> After we couldn’t get VoLTE running with srsenb, we replaced it  with an
> Amarisoft eNB from a second System (Amarisoft-OTS) and the configuration
> with the two Amarisoft systems worked.
> 
>  
> 
> Maybe someone has more experience in connecting an srsENB to an
> Amarisoft MME + IMS than me and my team and could give some advice onto
>  where we have to look at in our configuration to make VoLTE work.
> 
>  
> 
> If needed I could provide PCAP and log-files from srsenb and Amarisoft
> Callbox.
> 
>  
> 
> Sincerely
> 
>  
> 
> Norbert
> 
> 
> _______________________________________________
> srslte-users mailing list
> srslte-users at lists.softwareradiosystems.com
> https://lists.softwareradiosystems.com/mailman/listinfo/srslte-users
>